They looked at the effects of pregnancy drinking on five-year-olds. The team studied1,628 mothers and their children.

Kids of mothers who were low to moderate drinkers during pregnancy (1-8 drinks per week) showed no significant differences in brain development than kids of mothers who hadn't drank while pregnant. Even incidences of binge drinking did not appear related to neurodevelopmental problems in the five-year-olds.

And, kids whose mothers had completely abstained from drinking did not perform any better on IQ or executive function tasks than the children of low to moderate drinkers.

The one significant difference the researchers did find was that five-year-olds whose mothers drank heavily during pregnancy (more than 9 drinks per week) had lower attention spans than their peers.

So what to make of all this? Previous research has repeatedly suggested negative effects of drinking even just a small amount during pregnancy. A Time U.S. article recommends taking these findings with a grain of salt.

This data is notoriously hard to interpret, in part because it is based on women's self-reports: the public health message against drinking during pregnancy has been so widely adopted that women who do drink may significantly underreport their consumption to researchers. If women who say they are drinking at "light" levels are actually drinking at moderately or heavily, that might make the data on light drinking look more dangerous than they are.

So maybe drinking really is not as dangerous to fetal development as we previously thought. But - and this is a huge but - fetal alcohol spectrum disorder remains the leading cause of developmental delays in children. No one can disagree with the fact that drinking can have effects on a developing baby, and when it does the impact can be devastating.